California Residents Urged to Limit Air-Con Use During Heat Wave

Residents in California have been urged to conserve their air-conditioning usage as an ongoing heat wave threatens to place increasing stress on the state's electrical grid.

Officials at both Pacific Gas & Electric (PGE), one of the state's six regulated, investor-owned electric utilities, and California Independent System Operator (CAISO) have called for reduced energy consumption at peak times while the hot weather lasts, according to local reports.

It comes as the Southwest is in the middle of a summer heat wave that has brought temperatures well above 100 degrees Fahrenheit to parts of several states, including California's Central Valley. On Sunday, a reading of 128 degrees was logged in Death Valley—just six degrees shy of the area's 1913 record of 134 degrees at Furnace Creek.

In its latest local forecast, the National Weather Service (NWS) is warning of "dangerously hot temperatures" through Monday. In Antelope Valley, north of Los Angeles, the mercury is expected to peak above 110 degrees Fahrenheit.

Over the weekend, the NWS station in the San Francisco Bay Area wrote on Twitter that it was relying on satellites after it had to power down its radar. This was "due to an air conditioning issue" that had been caused by the extreme temperatures.

As part of its summer energy advice, PGE suggests keeping the thermostat at 78 degrees Fahrenheit when residents are at home and 85 degrees when out, unless they are frail or sensitive to extreme heat.

PGE adds that every degree above 78 degrees Fahrenheit equates to around a 2 percent saving in energy costs. Even set to 78 degrees, an air-conditioning unit could potentially be running half of the time in hot weather. Customers who sign up to reduce their energy consumption during peak periods in the summer can receive credit on their bill.

PGE also recommends cooling homes earlier in the day, including through opening blinds and windows, so air conditioning does not have to be on during the evening peak in demand.

"With extremely hot temperatures across the Central Valley, customers are looking at ways to best conserve energy while still making sure they can stay safe and cool," Jeff Smith, a PGE spokesperson, told Newsweek.

"Peak usage tends to be between about 4 p.m. and 9 p.m., so [one] thing customers can do to save energy and positively impact their bills is to cool the house down further a little bit before 4 p.m.," he said.

Smith said that the call for reducing air conditioning usage had primarily been driven by a desire to help customers reduce summer energy costs, but it was "a little" to do with helping reduce demand.

CAISO has yet to issue any statewide flex alerts—which are used to warn residents to limit their energy consumption ahead of an anticipated shortage—as the worst of the record-nearing temperatures were only being seen in some parts of California.

"That tends to happen when we have hotter than average temperatures statewide, not just in one portion of the state as is the case with this particular heat wave," Smith noted.

On Thursday, CAISO wrote on Twitter that it was "closely monitoring" the hot weather and that "no energy supply shortages are anticipated." As of 1:15 a.m. local time (4.15 a.m. ET) on Monday, the grid operator has a capacity of 47,300 megawatts and forecasts the peak at 6 p.m. (9 p.m. ET) to be 44,302 megawatts.

A CAISO spokesperson stressed to Newsweek that while "we always encourage Californians to conserve electricity in general" it had no flex alerts or emergency declarations planned as of Monday.

However, officials at the grid operator told ABC 7 that residents should avoid using air-conditioning units and large appliances during the hottest parts of the day.

Ahead of a flex alert, residents are urged to pre-cool their home before the hottest part of the day, and set the air-conditioning unit to at least 78 degrees if one is issued.

Climate experts have warned that there will be more extreme weather events—including harsh storms, sweltering heatwaves and excessive flooding—and so electricity grids are facing increased stress.

Last summer, California told citizens to conserve energy to prevent strain on its grid during a similar heatwave, while a cold snap in December led to the temporary closure of oil refineries in the Gulf.

Grid stress is a growing concern. In 2020, U.S. households experienced an average of more than seven hours of power outages, the majority caused by extreme weather events, Energy Information Administration (EIA) data shows. This was compared with just over four hours in 2016.

Update 07/18/23, 2:42 a.m. ET: This article was updated to include comment from Jeff Smith, a PGE spokesperson, and a CAISO spokesperson.